Content Comparison

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usbd_audio.h / usbd_audio.c

Prototype

void  USBD_Audio_CfgAdd (CPU_INT08U   class_nbr,
                         CPU_INT08U   dev_nbr,
                         CPU_INT08U   cfg_nbr,
                         USBD_ERR    *p_err);

Arguments

class_nbr

Class instance number.

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1. If USBD_Audio_CfgAdd() is called several times from the application, it allows to create multiple instances and multiple configurations. For instance, the following architecture could be created:
   

   Audio Class 0 (device number 0)

       |-- Configuration 0

       |-- Configuration 1

   Audio Class 1 (device number 1)

       |-- Configuration 0

       |-- Configuration 1

    

2. The Configuration Descriptor corresponding to an audio device has the following format:

   Configuration Descriptor

   |-- Interface Descriptor (AudioControl)                                [standard]
       |-- Header Descriptor                                              [class-specific]

       |-- Unit Descriptor(s)                                             [class-specific]

       |-- Terminal Descriptor(s)                                         [class-specific]

   |-- Endpoint Descriptor (Interrupt IN) - optional                      [standard]

       |-- Interface Descriptor (AudioStreaming)                          [standard]

       |-- AS Interface Descriptor                                        [class-specific]

           |-- AS Format Type Descriptor                                  [class-specific]

       |-- AS Format-Specific Descriptor(s)                               [class-specific]

       |-- Endpoint Descriptor (Isochronous IN or OUT Data)               [standard]

           |-- AS Isochronous Audio Data Endpoint Descriptor              [class-specific]

           |-- Endpoint Descriptor (Isochronous OUT or IN Synch endpoint) [standard]

       |-- Interface Descriptor (AudioStreaming)                          [standard]

           |-- ...

       |-- Interface Descriptor (AudioStreaming)                          [standard]

           |-- ...

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